Diagnosis of myelopathy whatever its cause, is based on clinical findings: paraparesis, loss of sensibility, sphincterian disturbance. Diagnosis of myelopathy requires magnetic resonance imaging, which rules out compressive and vascular disorders. Main causes of inflammatory myelopathies are multiple sclerosis multisystemic disorders, infectious and post-infectious diseases. Absence of identifiable causes in one quarter of the cases leads to the diagnosis of idiopathic myelitis.